1. Field of the Invention
The present invention relates generally to a core network separation structure and a signal processing method thereof, and in particular, to separation of packet data processing elements and signaling processing elements in a packet-switched domain and a signal processing method between the separated elements.
2. Description of the Related Art
A mobile communication system generally refers to a system that services voice and data over a wireless communication network. The mobile communication system is implemented in diverse ways and the major examples are a circuit switching network and a packet switching network.
A network for the mobile communication system should be so configured as to efficiently transmit voice and data. This network requirement will be more pressing in a future mobile communication system (IMT 2000) from which it is expected that an increased volume of data will be transmitted to provide multimedia services.
The future mobile communication system for which work is ongoing to establish standards defines the following network requirements.
(1) Independence of transmission technology for applying a transmission function from a higher service.
(2) Separation criteria whereby call processing is separated from transmission.
(3) Separation of technologies that will be evolved in different forms.
There has already been defined a core network separation structure on the above principles in a circuit-switched domain. FIG. 1 illustrates the core network separation structure of the circuit-switched domain in the circuit switching network of a conventional mobile communication system. As shown in FIG. 1, the conventional mobile communication system is divided largely into a circuit switching network and a packet switching network. The circuit switching network processes circuit data including voice and the packet switching network processes packet data.
Referring to FIG. 1, an MSC (Mobile Switching Center) being a core network (CN) in the circuit-switched domain is separated into an MSC server and a media gateway (MGW). The MSC server is connected to a UTRAN (UMTS Terrestrial Access Network) through a predetermined signaling interface and processes signaling in the circuit-switched domain. That is, the MSC server processes signaling necessary to interface circuit data with the UTRAN or a GMSC (Gateway MSC). The UTRAN includes plurality of Node B which corresponds to a (BTS (Base station transmission System) connected to respective RNC(Radio Network Controller) and MSC. The MGW is connected to the UTRAN through a predetermined data transfer interface and switches circuit data in the circuit-switched domain. For this purpose, a protocol must be defined between the MSC server and the MGW to exchange information. MeGaCo (Media Gateway Control) protocol of IETF, which is also defined in H.248 of ITU-T, is adopted for example. Meanwhile, the GMSC connected to the PSTN (Public Switched Telephone Network) is separated into a GMSC server and an MGW. The MGW of the GMSC is connected to the MGW of the MSC through a predetermined data transfer interface and switches circuit data between the PSTN and the CN. The GMSC server is connected to the MSC server through a predetermined signaling interface and processes signaling required for switching circuit data between the PSTN and the CN. For this purpose, a protocol must be defined between the GMSC server and the MGW of the GMSC to exchange information.
As described above, the circuit switching network in the conventional mobile communication system has separate circuit data processing elements (the MGWs) and signaling processing elements (the MSC server and GMSC server).
However, a core network separation structure of the packet-switched domain is yet to be explored in the packet switching network. In the existing defined core network structure of the packet-switched domain, the UTRAN is connected to an SGSN (Serving GPRS (General Packet Radio Service) Support Node) through a predetermined signaling and data transfer interface. The SGSN is connected to a GGSN (Gateway GPRS Support Node) via a signaling and data transfer interface. On the other hand, the GGSN is connected to multimedia IP (Internet Protocol) networks. The SGSN functions for switching and signaling to interface packet data with the UTRAN. The GGSN switches and processes signaling to interface packet data with the multimedia IP networks.
The core network in the packet-switched domain has not yet been separated into elements. While some separation structures for the SGSN have been proposed, there is no separation structure defined for the GGSN. Besides exploration of a separation structure for the core network in the packet-switched domain, an information flow between separated elements should be defined in detail at the same time.